import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class Test{
    public int add(int a,int b){
        try {
            return a+b;
        }
        catch (Exception e) {
            System.out.println("catch语句块");
        }
        finally{
            System.out.println("finally语句块");
        }
        return 0;
    }
    public static void main(String argv[]){
        Map<Object,Object> map = new ConcurrentHashMap<>();
        map.put("1","1");
        Map<Object, Object> objectObjectMap = Collections.synchronizedMap(new HashMap<Object, Object>());
        System.out.println(map.get("1"));
    }
}
